Patent Application
20110224575
Needle catheters are often employed to inject medication into a body, obtain fluid and/or tissue samples, etc. In these procedures, a needle is advanced to a target tissue site guided using endoscopic vision systems or other imaging techniques (e.g., ultrasound). The needle is then advanced distally from the catheter to penetrate the target location. In biopsy procedures, suction is then applied (e.g., via a syringe) to draw desired sample tissue into the needle. During this process, the needle may be moved back and forth repeatedly to harvest the desired sample, which is drawn through the needle to a proximal end thereof for analysis. In these cases, tissue trauma is increased due to the increased friction between the needle catheter and the skin and intervening tissue.
The present invention is directed to a device for penetrating tissues within a living body, comprising a shaft extending from a proximal end which, in an operative position, remains outside the body to a distal end which, in the operative position, is within a living body the shaft comprising a working channel extending therethrough from the proximal end to the distal end comprising an opening. The device also comprises a needle extending within the working channel, the needle comprising a tissue penetrating distal tip, a portion of an outer surface of the needle including a first structure extending along a path wrapping around a portion of a length of the needle, the first structure configured to mate with a second structure formed on a corresponding portion of an inner wall of the shaft, the first and second structures mating with one another so that, as the needle is urged axially through the working channel, the first and second structures cause the needle to rotate about an axis of the working channel.
The present invention, which may be further understood with reference to the following description and the appended drawings, relates to a device for rotating a biopsy needle within the body. It is noted that although the exemplary embodiment of the present invention is described with respect to particular procedures within a living body, the description is not meant to limit the application of the invention, which may be employed in any of a number of procedures requiring the insertion of a needle into a living body.
When performing a biopsy procedure, it is often desirable to screw the needle into the target tissue without coring. This motion allows tissue samples to be captured with less need for suction and the consequent drawing of blood and other non-targeted tissues into the needle. This motion, known as juicing, is generally performed by manually rotating the proximal end of the device to transmit the torque along the device shaft to rotate the needle at the distal end. Unfortunately, this rotation causes the shaft of the device to wind up (i.e., twist), reducing the rotation of the distal tip of the needle when compared to the degree of rotation of the proximal handle. Furthermore, rotating the entire needle catheter may cause pain and injury or result in whipping, as those skilled in the art will understand.
Devices and methods according to an exemplary embodiment of the present invention permit rotation of the distal tip of a needle without requiring rotation of the proximal end thereof. Specifically, the user applies to the device only axially directed forces (i.e., forces directed along a longitudinal axis of the device). A portion of this force is converted at the distal end of the device to a rotational force generating a desired rotation of a needle about the axis.
As shown in
A distal portion 108 of the needle 102 including the puncturing tip 104 is rotatably attached to a proximal shaft 110 via a rotating joint 112. The joint 112 may allows for any desired degree of rotation between the shaft 110 and the distal portion 108 of the needle 102 and preferably allows for an unlimited range of free rotation. As will be made clear later, any desired limits to the permitted degree of rotation of the distal portion 108 relative to the shaft 110 may be set through the construction of a mechanism for translating axial motion of the shaft 110 into axial and rotational movement of the distal portion 108. However, any desired limit to relative rotation between these parts may also be set through the construction of the joint 112. Furthermore, as would be understood by those skilled in the art, the joint 112 also preferably includes a lumen (not shown) extending therethrough to couple a lumen 114 of the distal portion 108 to a lumen 116 in the shaft 110. The lumen (not shown) thus permits samples to be drawn through the shaft 110 out of the body without removing the device 100 from the body. The lumen of the joint 112 is preferably coupled with the lumens 116 and 114 to provide a smooth unobstructed flow path for materials passed therethrough, thereby preventing any trauma, damage or flow resistance to said materials.
The needle 102 of the device 100 contains a groove 118 extending along a substantially helical path around a portion of an axial length of the needle 102. Specifically, the groove 118 spans a distance D1 along the needle 102 and terminates at a predetermined distance from the distal end of the needle 102. In an exemplary embodiment, a pitch of the helical groove 118 is selected so that a predetermined amount of axial movement of the needle 102 causes a rotation of approximately 360°, although any other pitch may be employed without deviating from the scope of the present invention. It is noted that although the groove 118 is depicted as extending along only a predetermined distal length of the needle 102, in an alternate embodiment the groove 118 may extend for substantially the entire length of the needle 102. As will be described below in greater detail below, the groove 118 provides for the rotation of the needle 102 upon entry and withdrawal thereof from the catheter shaft 106. A width W1 of the groove 118 is substantially equal to or slightly greater than a width W2 of an abutment 120 located on the inner portion of the catheter shaft 106, the groove 118 providing clearance for the sliding of the abutment 120. A height of the abutment 120 relative to a depth of the groove 118 is preferably selected to prevent the removal of the abutment 120 from the groove 118 at any location other than a distal end of the groove 118. During insertion into and removal from the body and when moving within the body between separate target sites, the needle 102 is preferably maintained in a retracted state with the abutment 120 located in a distal most portion of the groove 118 and a pointed distal tip of the needle 102 housed within the catheter 106. Accordingly, a distance D2 corresponding to an axial distance from a distal end of the abutment 120 to a distal end of the catheter 106 may be substantially equal to or greater than a distance D3 corresponding to a length of the needle between a distal most portion of the groove 118 and the distal end of the puncturing tip 104. It is noted however, that the distance D2 may also be smaller than the distance D3 without deviating from the scope of the present invention. In such an embodiment, the groove 118 may be positioned proximally of the abutment 120 in an insertion configuration and may only be brought into contact with the abutment after the catheter shaft 106 has been brought to a target tissue site in the body so as to prevent trauma to untargeted tissue during insertion, as those skilled in the art will understand. In an alternate embodiment incorporating a cap or other structure to protect surrounding tissue from the puncturing point 104, the distance D2 may be smaller than the distance D3.
As the shaft 110 is moved axially in a distal direction via actuation of an actuator on the handle 130 and the needle 102 is extended distally from the catheter shaft 106, the abutment 120 is forced to slide along the groove 118. This causes the needle 102 to rotate (clockwise as viewed looking proximally) as it moves distally.
The abutment 120 also serves to prevent the needle 102 from being extended distally from the catheter 106 beyond a predetermined length. For example, the axial length D1 of the groove 118 is preferably chosen to permit the needle 102 to protrude distally from the catheter shaft 106 only by a certain distance selected, for example, on the needs of the particular procedure being performed and the mechanical properties of the device 100, as those skilled in the art will understand. After a procedure has been completed, the user of the device 100 retracts the needle 102 by moving the proximal handle portion 140 and the first actuator along at central actuation portion 136 of the handle 130. Specifically, movement of the first actuator 132 in a proximal direction toward the proximal handle portion 140 causes retraction of at least a portion of the device 100 into the handle 130. Movement of the first actuator 132 distally away from the proximal handle portion 140 likewise generates distal movement of the needle 102 until the puncturing tip 104 of the needle 102 is fully exposed outside of the catheter 106. It is noted that the design of the handle 130 may take any desired shape as dictated, for example, by ergonomics, etc. and is not limited to the arrangement shown in the embodiment of
This exemplary embodiment allows the rate of rotation and the orientation of the puncturing tip 104 of the needle 102 to be controlled to desired rates. Furthermore, as would be understood by those skilled in the art, by varying the pitch or helix angle of the groove 118 along its length, a ratio of the rotational speed of the catheter relative to the axial movement thereof may vary. For example, to ease the start of rotation of the needle 102, the helix angle may be reduced at both the proximal and distal ends of the groove 118 and, then steepen to speed the rotation of the needle as the abutment travels along a middle portion of the groove 118. In addition, since the abutment 120 engages the groove 118 with a substantially tight friction fit, undesired movement of the needle 102 is prevented, improving the accuracy of the movements of needle 102 and eliminating the need for a user of the device 100 to directly apply rotational forces to the proximal end to avoid problems associated therewith (e.g., wind up, whipping, etc.).
As shown in
As would be understood by those skilled in the art, the aforementioned operation may be automated using known mechanisms. For example, such a mechanism can be coupled to the actuator which applies axial force to the shaft 210 so that, when a user of the device 200 actuates the actuator to withdraw the needle 202 proximally, the pawl 220 is retracted into the recess 228 out of engagement with the groove 218 allowing the needle 202 to withdraw into the catheter shaft 206 without rotating. If the pawl 220 is allowed to spring back against the surface of the needle 202 after being withdrawn from the groove 218, proximal surfaces of portions of the groove 218 circumferentially aligned with the proximal and distal ends of the groove 218 may be ramped to allow the pawl 220 to ratchet therepast as the needle 202 is retracted proximally until the pawl 220 enters and locks into the proximal end of the groove 218. The device 200 thus minimizes rotation of the needle 202 through the tissue reducing trauma thereto.
As mentioned above, the selected portion 416 of the inner wall 418 is threaded to mate with a correspondingly threaded portion 426 of the needle member 410. The threading engagement of the portion 416 of the inner wall 418 and the portion 426 of the needle member 410 causes the needle member 410 to rotate about its longitudinal axis as it is moved axially through the outer member 402, wherein one or both of the inner wall 418 and the threaded portion 426 are lubricated to better encourage rotation. Since an inner diameter of a portion of the working channel 404 distal of the portion 426 of the needle member 410 is smaller than a maximum diameter of the portion 426, the position of the distal end of the portion 416 defines a maximum extent of projection of the needle member 410 beyond the distal end of the outer member 402. Similarly, since an inner diameter of a portion of the working channel 404 located proximally of the portion 426 of the needle member 410 is smaller than a maximum diameter of the portion 426, the position of the proximal end of the portion 416 defines a maximum extent of withdrawal of the needle member 410 proximally into the working channel 404.
Operation of an actuator 428 on the handle 406 urges the needle member 410 distally and withdraws it proximally substantially along a longitudinal axis of the outer member 402—i.e., axially within the working channel 404. As would be understood by those skilled in the art, the actuator 428 may operate in the manner of any known mechanism for moving a needle axially through a working channel provided the needle member 410 is free to rotate about its longitudinal axis relative to the handle 406. In a preferred embodiment, an actuating mechanism for the needle member 410 may be manually driven by the actuator 428 wherein a reciprocal motion of the actuator 428 is translated to a swiveling proximal-distal movement of the needle member 410. As the needle member 410 moves proximally and distally through the working channel 404, the threaded engagement of the portion 416 of the inner wall 418 and the portion 426 of the needle member 410 causes the needle member 410 to rotate about its axis, causing a corresponding rotation of the distal end of the needle member 410 and the tissue penetrating distal tip 414. This allows the tip 414 to screw into the target tissue without puncturing or coring. This motion allows tissue samples to be captured within the lumen 422 with less need for suction and the consequent drawing of blood and other non-targeted tissues into the lumen 422. This motion substantially mimics a maneuver (juicing) currently performed manually by moving the entire device proximally and distally to drive the tip of a biopsy needle repeatedly into engagement with target tissue. However, the more controlled overall movement and ratio of rotation to linear advancement provided by the device 400 allows for the optimization of this motion to maximize tissue sample quality while minimizing trauma to the surrounding tissue.
A distal portion of the needle member 410 may include a plurality of surface incongruities (e.g., projections 450) extending along a path substantially parallel to a path of the threading of the portion 426 so that, as the needle member 410 is screwed into tissue, the projections 450 rotate along a path substantially similar to that of the portion 426 and, by providing echo-sonic reflection areas when used in conjunction with ultrasound imaging, indicate to a user the precise linear and rotational motion of the distal tip 414 of the needle member 410. The projections 450, in addition to serving as echo-reflectors, also help a user to visualize rotation of the needle member 410 and to provide rotation thereto as the needle member 410 slides against the inner wall 418, the projections being formed of for example, a lubricious polymer such as TFE. Those skilled in the art will understand that the projections 450 are sized to provide a clear image of the motion of the distal end of the needle member 410 but that they preferably project from the outer surface of the needle 426 by a distance which allows the distal tip 414 to be fully withdrawn into the working channel 404 (i.e., the outer diameter of the portion of the needle member 410 including the projections 450 is less than the inner diameter of the distal portion of the working channel 404). In another embodiment of the invention the projections 450 may be formed as any surface features permitting echo-reflection (i.e., raised portions, indentations, insets, etc.). For example, indentations (not shown) provided on the needle member 410 may be formed as one continuous, threadlike spiraling indentation extending around the needle member 410 to permit a screw-like insertion of the needle member 410 into the tissue when coming into contact with a corresponding threading or abutment formed on an outer wall of the working channel 404 or as a plurality of separate indentations spaced from one another to permit an axial insertion into tissue. In another example, insets made of a material with a high echo-reflectivity may be embedded on an outer surface of the needle member 410 to provide a reflective advantage over a solid needle member 410. The insets may be provided in any patterns such as a spiral pattern selected to match a corresponding thread in the working channel 404 and permit a screw-like movement of the needle member 410 thereoutof. The surface features discussed above may be provided from a proximal end located proximally of a needle taper to a distal end of the needle member 410. In a preferred embodiment, the surface features may function as both reflecting agents and as screw guides to permit screwable insertion of the needle member 410 into a target portion of tissue.
The present invention may be applied to medical and scientific procedures that require the insertion of a needle into tissue. Though the present invention has been described with respect to the retrieval of tissue samples, it is submitted that many alternate uses such as, for example, mechanisms according to this invention may be employed for the needles for injection or withdrawal of fluids may be employed without deviating from the spirit and scope of the present invention. For example, the translation of movement to a rotational mechanism as disclosed herein may be applicable to any medical device requiring the rotation of a distal tip upon actuation thereof, the medical device including, but not limited to cytology brushes, biopsy needles, snares, fluid sprayers, optic fibers, cutting tools, biopsy forceps, graspers, hooks and the like. Furthermore, although embodiments of the present invention are directed to a catheter sheet comprising an abutment and a needle having grooves, the present invention also covers embodiments wherein the abutments are formed on the needle and a groove is formed on the catheter shaft, as depicted in one embodiment in
This application claims the priority to the U.S. Provisional Application Ser. No. 61/312,374, entitled “NEEDLE WITH HELICAL GROOVES CONVERTING AXIAL MOVEMENT TO ROTATIONAL MOVEMENT” filed Mar. 10, 2010. The specification of the above-identified application is incorporated herewith by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61312374 | Mar 2010 | US |
